pthread_cond_wait

#include

#include

#include

#include

#include

#include

pthread_mutex_t mx = PTHREAD_MUTEX_INITIALIZER; //静态锁

pthread_cond_t *ct ;

pthread_t ntid_1 = 0;

pthread_t ntid_2 = 1;

int common = 1;

void printpid(void);

void *thr_fn_1(void* );

void *thr_fn_2(void* );

void cleanup(void *arg)

{

    printf("cleanup func : %s\n", (char *)arg);

}

void printpid()

{

    pid_t pid;

    pthread_t tid;

    pid = getpid();

    tid = pthread_self();

    printf("pid = %u, tid = %u\n", (unsigned int)pid, (unsigned int)tid);

}

void *thr_fn_1(void* arg)

{

    printf("pthread one start\n");

    pthread_cleanup_push(cleanup, "thread 1 first handler");

    pthread_mutex_lock(&mx);   //给线程加锁

    printf("thread 1 push complete. \n");

    common += 1;

    printf("common = %d\n", common);

    printpid();

    sleep(3);              

    common += 1;

    printf("common = %d\n", common);

    pthread_cleanup_pop(1);

    printf("pthread one end\n");

    pthread_mutex_lock(&mx);   //解锁线程

    pthread_cond_signal(ct);   //执行完后发送信号

    return ((void*)1);

}

void *thr_fn_2(void* arg)

{

    printf("pthread two start\n");

    pthread_cleanup_push(cleanup, "thread 2 first handler");

    while(1){

        pthread_cond_wait(ct, &mx);  //得到信号继续执行

        break;

    }

    common -= 1;

    printf("common = %d\n", common);

    printf("thread 2 push complete. \n");

    printpid();

    pthread_cleanup_pop(1);

    printf("pthread two end\n");

    pthread_exit((void *)2);

}

int main(void)

{

    int err;

    void *tret;

    ct = malloc(sizeof(pthread_cond_t));  

    pthread_cond_init(ct, NULL); //初始化条件变量

    err = pthread_create(&ntid_1, NULL, thr_fn_1, NULL);

    if (err != 0) printf("err 1\n");

    err = pthread_create(&ntid_2, NULL, thr_fn_2, NULL);

    if (err != 0) printf("err 1\n");

    if( pthread_join(ntid_1, &tret) == EINVAL ) printf("has detach !\n");

    printf("thread 1 exit code %d\n", (int)tret);

    pthread_join(ntid_2, &tret);

    printf("thread 2 exit code %d\n", (int)tret);

    pthread_cond_destroy(ct);  //动态分配需要释放条件变量

    printf("main\n");

    printpid();

    exit(0);

}